Grinding apparatus

ABSTRACT

A tool support device for use in a belt grinding apparatus ( 1 ), the apparatus including, a drive motor ( 60 ), a drive shaft ( 61 ) and an abrasive belt arranged to be driven by the drive motor, ( 60 ) the tool support device ( 10 ) including a primary carriage ( 20 ) including a plurality of mounting zones ( 22, 23, 24 ) thereon, each mounting zone being adapted to receive a primary working tool assembly, ( 40, 41, 42 ), one or more of the primary tool assemblies including a secondary carriage ( 46 ) operatively mounted to the primary carriage ( 20 ) at one or respective one of the mounting zones ( 22, 23, 24 ) the primary carriage ( 20 ) being mounted for rotary movement so that it can adopt a plurality of working positions, wherein in each working position one of the primary working tools can be selectively disposed at a work station in an operative position, the secondary carriage ( 46 ) having a plurality of additional working tools thereon, the secondary carriage ( 46 ) being adapted for rotary movement relative to the primary carriage ( 20 ) so that one of the additional working tools can be disposed in an operative position when at the work station.

[0001] The present invention relates generally to grinding apparatus andmore particularly to apparatus using abrasive grinding belts.

[0002] Abrasive belt grinding apparatus are used in a variety ofapplications and can be used for flat grinding procedures or contourgrinding procedures. In many grinding applications such as for examplein knifemaking and other general grinding and polishing operationsrelative complicated contours are often required necessitating the useof a relatively large number of different tools. Such tools can be inthe form of contact wheels of different diameters over which theabrasive belt can pass. Most currently known apparatus are adapted toonly support one tool at a time. As such, it is necessary to continuallychange tools where complicated contours are being formed This is notonly time consuming but costly.

[0003] In U.S. Pat. No. 4,434,584 there is described turret belt grinderwhich is adapted to support different size contact wheels in a supportframe with an abrasive belt extending over the wheels. The frame isadapted to be rotated relative to mounting structure and is adapted forrotation relative thereto so that each wheel can be rotated to a commonwork station. The abrasive belt is driven by a V-belt which transmitspower from a centrally located motor shaft to a contact drive wheel.This device suffers from several drawbacks. For example, in order toaccess internal square corners the number of tools which can be carriedby the support frame is limited to three. In addition the drivearrangement is complicated and limits the functionality of the device.

[0004] Another problem associated with abrasive belt grinding apparatusis control of the belt during operation Belt tracking devices are knownbut are usually relatively complicated and can be unreliable.

[0005] It is therefore an object of the present invention to provideapparatus which alleviates one or more of the aforementioned problems.

[0006] According to one aspect of the present invention there isprovided a tool support device for use in a belt grinding apparatus, theapparatus including, a drive motor, a drive shaft, and an abrasive beltarranged to be driven by the drive motor. The tool support deviceincludes a primary carriage operatively connectable to a supportstructure, the primary carriage including a plurality of mounting zonesthereon, each mounting zone being adapted to receive a primary workingtool assembly, one or more of the primary tool assemblies including asecondary carriage operatively mounted to the primary carriage at one orrespective ones of the mounting zones, the primary carriage beingmounted for rotary movement so that it can adopt a plurality of workingpositions, wherein in each working position one of the primary workingtools can be selectively disposed at a work station in an operativeposition, the secondary carriage having a plurality of additionalworking tools thereon, the secondary carnage being adapted for rotarymovement relative to the primary carriage so that one of the additionalworking tools can be disposed in an operative position when at the workstation.

[0007] The apparatus may be arranged so that there is a single workstation or multiple work stations. When in use the abrasive belt isadapted to be entrained around at least some of the primary toolassemblies.

[0008] In one preferred form, the primary carriage may include threemounting zones, each of the zones being adapted to receive a respectiveprimary tool assembly. Two of the primary tool assemblies may be in theform of contact wheels of different diameter. The additional workingtools on the or each secondary carriage may also be in the form ofcontact wheels which are of different diameter to the first mentionedcontact wheels. Desirably, because there are only three mounting zones,this permits tools in each zone to be capable of grinding internalradiuses in square corners.

[0009] In one preferred embodiment the primary carriage may include aplate like body mounted to a support structure for rotation about anaxis of rotation. Preferably, the primary carriage is mounted to thehousing of the motor of the grinding apparatus.

[0010] Preferably, the plate-like body of the carriage is generallytriangular in shape with the mounting zones being disposed in thegeneral region of the three apexes of the triangular shaped plate.Preferably, the angle of the plate like body at each of the apexes isless than 90°.

[0011] In a preferred form of the invention when in the assembledposition, the drive shaft of the motor is operatively connected to oneof the contact wheels so as to generally coaxial therewith, this contactwheel causing movement of the abrasive belt over the other working toolassemblies. Preferably, rotation of the primary carriage is about theaxis of the drive shaft.

[0012] The device may further include a platen operatively connected tothe primary carriage body in a position between the mounting zones. Theplaten is arranged adjacent the abrasive belt when in use for use inflat grinding operations.

[0013] The secondary carriage may in one form include a carriage bodywhich is mounted for rotation on the primary carriage at one or two ofthe mounting zones so that it can adopt a plurality of operativepositions. The secondary carriage body may include a hub section andthree sets of generally radially extending mounting arms each set ofmounting arms being adapted to support a respective contact wheel.Locking means which may be in the form of a releasable locking pin maybe provided to lock the secondary carriage relative to the primarycarriage in a selected one of its operating positions.

[0014] The device may further include a locking assembly for releasablyholding the primary support carriage in a selected one of its operatingpositions. In one form, the locking assembly may include a mountingplate having a plurality of locating recesses therein, the mountingplate being attached to the housing of the motor. A detent isoperatively connected to the carriage through an adjustment arm, thedetent being adapted to cooperate with the locating recesses to hold thecarriage relative to the motor in one of a selected number of operatingpositions. A spring may be arranged to urge the detent into engagementwith a selected one of the locating recesses.

[0015] Preferably, at least some of the tool assemblies are operativelymounted to the primary carnage by means of adjustable generally conicalshaped mounting pivots. By this arrangement any wear between the partscan be adjusted for. This feature is particular valuable in provided foraccurate tracking of the belt over the tool assemblies. Furthermore, lowfriction material such as Teflon preferably in the form of a layer maybe provided between the primary carriage and the tool assembly.

[0016] The apparatus may further include a belt tensioning device whichin one form includes a lever and slot assembly which causes movement oftool assembly relative to the support carriage to thereby relieve orapply a tension to the belt.

[0017] One or more safety shields may be provided at the mounting zones.In a preferred form the or each safety shield may include a main bodymounted to the primary carriage for pivotal movement relative theretobetween a retracted position and an in use position The shield furtherincludes a cover portion which in the in use position overlies the belt.

[0018] According to another aspect of the present invention there isprovided a tracking adjustment mechanism for correcting the tracking ofa belt on a belt drive. The mechanism including an axle assemblyoperatively mounted to a support carriage, the assembly including anaxle upon which a contact wheel is mounted for rotation, the axleincludes opposed end bearings one of which provides for at least limitedpivotal movement of the axle. Preferably, the limited pivotal movementin is the form of limited universal movement. The bearing may include anadjustable ball and socket assembly. The other bearing may include aneccentric thereon which is operable by a lever so that rotation of theeccentric causes pivotal movement of the axle in the other bearingthereby adjusting the position of the axle relative to the supportcarriage. This tracking adjustment mechanism may be used in the toolsupport device according to the first mentioned aspect of the invention.

[0019] Preferably, the tracking mechanism includes an axle assemblywhich is mountable to the primary carriage via mounting brackets, eachhaving a bearing mounting therein. One of the bearing mountings may bein the form of a curved mounting surface in the mounting bracket whichis complementary in shape to a portion of a sphere. The other bearingmounting may be in the form of a circular aperture in mounting bracket.

[0020] The axle assembly may further include an axle having endbearings, these end bearings being receivable within respective bearingmountings on the mounting brackets. The end bearing may be in the formof a at least part hemispherical ball which in the assembled position isadapted to be disposed within the curved mounting surface of the bearingmounting. The bearing may be in the form of a head of a screw elementwhich is securable to axle. An adjustment nut enables the bearing to betightly received within the bearing mounting socket and enablessubsequent adjustment if wearing occurs.

[0021] The other bearing may be in the form of a collar which iseccentrically disposed with respect to the longitudinal axis of theaxle. The collar is receivable within bearing mounting and can berotated therein by means of actuating lever. A spring which may be inthe form of a disc spring ensures that the various parts are held in atight relationship with respect to one another.

[0022] It will be appreciated that the apparatus of the presentinvention can provide up to seven different tools with each tool beingable to access an internal square corner of the component being worked.

[0023] Preferred embodiments of the invention will be hereinbeforedescribed with reference to the accompanying drawings, and in thosedrawings:

[0024]FIG. 1 is a rear view of grinding apparatus having a tool supportdevice according to the present invention;

[0025]FIG. 2 is a front view of the apparatus shown in FIG. 1;

[0026]FIG. 3 is a front view of the apparatus showing the lockingassembly of the tool support device;

[0027]FIG. 4 is a detail of the belt tensioning assembly of the toolsupport device;

[0028]FIG. 5 is a front detail of the secondary carriage of the toolsupport device;

[0029]FIG. 6 is a rear view of the secondary carriage shown in FIG. 5;

[0030]FIG. 7 is a partial sectional view detailing the mounting of atool assembly to the primary carriage; and

[0031]FIG. 8 is a sectional view detailing the tracking mechanismaccording to one aspect of the present invention.

[0032] Referring to the drawings there is shown a grinding apparatusgenerally indicated at 1 which includes a drive motor in the form of anelectric motor 60 having a drive shaft 61. The motor is mounted on astand 63 or for example, a right hand corner of a bench or table.

[0033] The tool support device generally indicated at 10 includes aprimary carriage 20 which is operatively connected to a section of thedrive motor 60. The carriage 20 includes a generally plate like bodywhich is generally triangular in shape, the body being mounted to themotor for movement about a rotation axis X so that it can adopt aplurality of different operating positions. A locking mechanism 30 isprovided to lock the carriage with respect to the motor housing. Thelocking mechanism 30 includes a mounting plate 32 having a plurality oflocating recesses 34, 36, 37, 38, and 39 therein, the mounting platebeing attached to the housing of the motor. Limit stops 78 and 79 limitrotation of the carriage 20 relative to axis X. A detent 31 isoperatively connected to the carriage 20 through an adjustment arm 35,the detent being adapted to cooperate with the locating recesses to holdthe carriage relative to the motor in one of a selected number ofoperating positions. A spring 33 is arranged to urge the detent intoengagement with a selected one of the locating recesses.

[0034] The primary carriage 20 further includes a plurality of mountingzones 22, 23, and 24, each zone being adapted to receive in a mountedposition a selected primary working tool assembly 40, 41, and 42. Two ofthe tool assemblies 41 and 42 are in the form of contact wheels ofdifferent diameters. A platen 43 and table 45 are provided between theassemblies 40 and 41. The contact wheels are for use in the contourgrinding and the platen is for use in flat grinding.

[0035] Another of the tool assemblies 40 includes a secondary carriage46 to which a plurality of additional tools are mounted. The additionaltools 47, 48 and 49 comprise contact wheels of various diameters. Thesecondary carriage 46 includes a hub portion 51 and three sets ofmounting arms 52, 53 and 54 which are fitted with bearings in those armsto which the contact wheels are mounted. The hub portion is adapted tobe rotated relative to the primary carriage so that each of thesecondary tools can be selectively positioned on an operative workingconfiguration A locking pin 55 locks the hub in the selected operatingposition.

[0036] Safety shields 56 are provided at some of the mounting zones. Theshield 56 includes a main body 58 and cover 57, the main body beingpivotally mounted to carriage via pin 59.

[0037] Referring to FIG. 7 there is shown an arrangement by which a toolassembly such as secondary carriage 46 can be mounted to the primarycarriage 20. The mounting includes a pivot member 65 which includes astem 66 and a conical section 67. Stem 66 is in threaded engagement withcarriage 20. The conical section 67 is received within a complementaryshaped aperture 75 in the secondary carriage 46. A tightening nut 76 isfitted to the stem 66 of the pivot member. A teflon panel or layer 77 isdisposed between the primary carriage 20 and the secondary carriage 46.The conical section 67 ensures that there is not excessive clearancebetween the two parts and facilitates adjustment if or when wear occurs.Spring loaded locking pin 55 locks the hub of the secondary carriageinto a selected operating position Pin 55 passes through a hardened bushin the carriage 20.

[0038] A continuous or endless belt 80 is arranged to extend at leastpartially around or over the tool assemblies.

[0039] As shown one of the primary tool assemblies 42 is operativelyconnected to the drive shaft of the motor so that rotation thereofcauses rotation of the belt around the various tool assemblies.

[0040] The apparatus further includes a belt tensioning device 70 whichcauses movement of tool assembly 41 relative to the support carriage 20to thereby relieve or apply a tension to the belt about pivot axis X. AFining catch 71 with slot assembly 72 locks the tensioning device 70 inthe retracted position to facilitate belt changing. Spring 73 urges thedevice 70 and thereby the tool assembly 41 into a position which placesthe belt under tension.

[0041] The tracking mechanism generally indicated at 80 includes an axleassembly 87 which is mountable to the prim carriage 20 via mountingbrackets 90 and 91, each having a bearing mounting 92 and 93 therein.One of the bearing mountings 92 is in the form of a curved mountingsurface in mounting bracket 90 which is complementary in shape to aportion of a sphere. The other bearing mounting 93 is in the form of acircular aperture in mounting bracket 91.

[0042] The axle assembly 87 comprises an axle 82 having end bearings 84and 85, these end bearings being receivable within respective bearingmountings 92 and 93 on the mounting brackets 90 and 91. The end bearing84 is in the form of a at least part hemispherical ball which in theassembled position is adapted to be disposed within the curved mountingsurface of the bearing mounting 92. The bearing 84 is in the form of ahead of a screw element 86 which is securable to axle 82. An adjustmentnut 89 enables the bearing 84 to be tightly received within the bearingmounting socket 92 and enables subsequent adjustment if wearing occurs.

[0043] Bearing 85 is in the form of a collar 81 which is eccentricallydisposed with respect to the longitudinal axis of the axle 82.Preferably, the collar 81 is foamed of a material which has someresilience such as example plastics such as urethane preferably arelative hard urethane. The collar 81 is receivable within bearingmounting 91 and can be rotated therein by means of actuating lever 88. Aspring in the form of a wave spring 83 ensures that the various partsare held in a tight relationship with respect to one another. A furtherspring 98 is provided at the other end of the assembly.

[0044] The reference to any prior art in this specification is not, andshould not be taken as, an acknowledgment or any form of suggestion thatthat prior art forms part of the common general knowledge in Australia.

[0045] Finally, it is to be understood that various alterations,modifications and/or additions may be incorporated into the variousconstructions and arrangements of parts without departing from thespirit or ambit of the invention.

The claims defining the invention are as follows:
 1. A tool supportdevice for use in a belt grinding apparatus, the apparatus including; adrive motor, a drive shaft, and an abrasive belt arranged to be drivenby the drive motor, the tool support device including a primary carriageoperatively connected to a support structure, the primary carriageincluding a plurality of mounting zones thereon, each mounting zonebeing adapted to receive a primary working tool assembly, one or more ofthe primary tool assemblies including a secondary carriage operativelymounted to the primary carriage at one or respective ones of themounting zones, the primary carriage being mounted for rotary movementso that it can adopt a plurality of working positions, wherein in eachworking position one of the prim working tools can be selectivelydisposed at a work station in an operative position, the secondarycarriage having a plurality of additional working tools thereon, thesecondary carnage being adapted for rotary movement relative to theprimary carriage so that one of the additional working tools can bedisposed in an operative position when at the work station.
 2. A toolsupport device according to claim 1 wherein the primary carriageincludes three mounting zones, each of the zones being adapted toreceive a respective primary tool assembly.
 3. A tool support deviceaccording to claim 2 wherein two of the primary tool assemblies are inthe form of contact wheels of different diameter.
 4. A tool supportdevice according to claim 2 wherein two said secondary carriages areprovided at respective mounting zones.
 5. A tool support deviceaccording to claim 4 wherein additional working tools on the or eachsecondary carriage are in the form of contact wheels which are ofdifferent diameter to the first mentioned contact wheels.
 6. A toolsupport device according to any preceding claim wherein the primarycarriage includes a plate like body mounted to a support suture forrotation about an axis of rotation.
 7. A tool support device accordingto claim 6 wherein the plate-like body of the carriage is generallytriangular in shape with the mounting zones being disposed in thegeneral region of the three apexes of the triangular shaped plate.
 8. Atool support device according to any preceding claim wherein when in theassembled position, the drive shaft of the motor is operativelyconnected to one of the contact wheels so as to generally co-axialtherewith, this contact wheel causing movement of the abrasive belt overthe other working tool assemblies.
 9. A tool support device according toclaim 8 wherein rotation of the primary carriage is about the axis ofthe drive shaft.
 10. A tool support device according to any precedingclaim further including a platen operatively connected to the primarycarriage body in a position between the mounting zones, the platen beingarranged adjacent the abrasive belt when in use for use in flat grindingoperations.
 11. A tool support device according to any preceding claimwherein the secondary carriage includes a carriage body which is mountedfor rotation on the primary carnage at one or two of the mounting zonesso that it can adopt a plurality of operative positions, the carriagebody including a hub section and three sets of generally radiallyextending mounting arms each set of mounting arms being adapted tosupport a respective contact wheel.
 12. A tool support device accordingto claim 11 further including locking means in the form of a releasablelocking pin may be provided to lock the secondary carriage relative tothe primary carriage in a selected one of its operating positions.
 13. Atool support device according to any preceding claim further including alocking assembly for releasably holding the primary support carriage ina selected one of its operating positions, the locking assemblyincluding a mounting plate having a plurality of locating recessestherein, the mounting plate being attached to the housing of the motor,a detent operatively connected to the carriage through an adjustmentarm, the detent being adapted to cooperate with the locating recesses tohold the age relative to the motor in one of a selected number ofoperating positions, and a spring arranged to urge the detent intoengagement with a selected one of the locating recesses.
 14. A toolsupport device according to any preceding claim wherein at least some ofthe tool assemblies are operatively mounted to the primary carriage bymeans of adjustable generally conical shaped mounting pivots.
 15. A toolsupport device according to any preceding claim further including a belttensioning device which includes a lever and slot assembly which causesmovement of tool assembly relative to the support carriage to therebyrelieve or apply a tension to the belt.
 16. A tool support deviceaccording to any preceding claim further including a tracking adjustmentmechanism for correcting the tracking of the belt on the various toolassemblies, the mechanism including an axle assembly operatively mountedto a support carriage, the assembly including an axle upon which acontact wheel is mounted for rotation, the axle including opposed endbearings one of which provides for at least limited pivotal movement ofthe axle, the other bearing including an eccentric thereon which isoperable by a lever so that rotation of the eccentric causes pivotalmovement of the axle in the other bearing thereby adjusting the positionof the axle relative to the support carriage.
 17. A tool support deviceaccording to claim 16 wherein said limited pivotal movement is a limiteduniversal movement.
 18. A tool support device according to claim 16 orclaim 17 wherein said end bearing includes an adjustable ball and socketassembly.
 19. A tool support device according to claim 16, 17 or 18wherein the tracking mechanism includes an axle assembly which ismountable to the primary carriage via mounting brackets, each having abearing mounting therein, one of the bearing mountings being in the formof a curved mounting surface in the mounting bracket which iscomplementary in shape to a portion of a sphere, the other bearingmounting in the form of a circular aperture in mounting bracket.
 20. Atool support device according to claim 17 wherein the axle assemblyfurther includes an axle having end bearings, these end bearings beingreceivable within respective bearing mountings on the mounting brackets,the end bearing being in the form of a at least part hemispherical ballwhich in the assembled position is adapted to be disposed within thecurved mounting surface of the bearing mounting, the bearing being inthe form of a head of a screw element which is securable to axle, therefurther being provided an adjustment nut which enables the bearing to betightly received within the bearing mounting socket and enablessubsequent adjustment if wearing occurs.
 21. A tool support deviceaccording to claim 18 wherein the other bearing is in the form of acollar which is eccentrically disposed with respect to the longitudinalaxis of the axle, the collar being receivable within bearing mountingand rotated therein by means of actuating lever, and spring in the formof a wave spring ensures that the various parts are held in a tightrelationship with respect to one another.
 22. A tool support deviceaccording to any preceding claim further including a safety shieldlocated at at least one of said mounting zones said safety shieldincluding a mounting portion for the shield to the primary carriage forswinging movement between a first position in which the shield shroudoverlies the mounting zone and retracted position in which it is spacedfrom the work zone.
 23. A tracking adjustment mechanism for correctingthe tracking of a belt on a belt drive assembly, the mechanism includingan axle assembly operatively mounted to a support, the assemblyincluding an axle upon which a contact wheel is mounted for rotation,the axle including opposed end bearings one of which provides for atleast limited pivotal movement of the axle, the other bearing includingan eccentric thereon which is operable by a lever so that rotation ofthe eccentric causes pivotal movement of the axle in the other bearingthereby adjusting the position of the axle relative to the supportcarriage.
 24. A tracking adjustment mechanism according to claim 23wherein said limited pivotal movement is a limited universal movement.25. A tracking adjustment mechanism according to claim 23 or 24 whereinsaid on bearing includes an adjustable ball and socket assembly.
 26. Atracking mechanism according to claim 23, 24 or 25 including an axleassembly which is mountable to a primary carriage via mounting brackets,each having a bearing mounting therein, one of the bearing mountings inthe form of a curved mounting surface in the mounting bracket which iscomplementary in shape to a portion of a sphere, the other bearingmounting in the form of a circular aperture in mounting bracket.
 27. Atracking mechanism according to claim 26 wherein the axle assemblyincludes an axle having end bearings, these end bearings beingreceivable within respective bearing mountings on the mounting brackets,the end bearing being in the form of a at least part hemispherical ballwhich in the assembled position is adapted to be disposed within thecurved mounting surface of the bearing mounting, the bearing being inthe form of a head of a screw element which is securable to axle, and anadjustment nut enabling the bearing to be tightly received within thebearing mounting socket and enables subsequent adjustment if wearingoccurs.
 28. A tracking mechanism according to claim 27 wherein the otherbearing is in the form of a collar which is eccentrically disposed withrespect to the longitudinal axis of the axle, the collar beingreceivable within bearing mounting and can be rotated therein by meansof actuating lever, and a spring in the form of a disc spring ensuresthat the various parts are held in a tight relationship with respect toone another.